Module export 

Export writer for mushroomdb export.

Supports five formats:

• jsonl: nodes.jsonl, edges.jsonl, rules.jsonl (always deterministic)
• csv: nodes.csv and relationships.csv, the files mushroomdb import --nodes/--relationships reads, with typed headers (age:int); plus rules.jsonl when the store has rules
• cypher: graph.cypher, one statement per line, that this engine’s own query language reads back
• parquet: nodes.parquet, edges.parquet, rules.parquet (byte-identical output is NOT guaranteed across parquet-rs versions; use JSONL when byte-stable reproducibility is required)
• graphml: a single .graphml file (nodes + edges only; rules have no GraphML analogue) for import into generic graph viewers and analysis tools

Two runs on the same store state produce byte-identical JSONL and GraphML output (sorted by key / (edge_type, src, dst) / name — callers must pre-sort the slices).

Float precision loss

Value::Float values that are NaN or ±Inf are not representable in JSON or in GraphML’s numeric attribute types. They are serialised as JSON null (JSONL) or an empty <data> element (GraphML) rather than causing the export to fail. This is a lossy mapping; the original value is irrecoverable from the export. Stores that need exact float fidelity should use the binary backup command instead of export.

Structs

CypherLoss

What a Cypher export could not write, counted; the statements it did write are all valid.

ExportStats

What a streamed export wrote.

Slices

Sorted slices as a source, for callers that already hold them.

Enums

ExportFormat

Accepted export formats.

Traits

ExportSource

Where an export reads the store from: node by node and edge by edge, so an export holds one record at a time (see mushroomdb::GraphDb::for_each_node_for_export). Nodes arrive sorted by key and edges by (edge_type, src, dst).

Functions

write_csv

Write nodes.csv and relationships.csv to dest, plus rules.jsonl when there are rules.

write_cypher

Write graph.cypher to dest: one statement per line, no terminator, the way mushroomdb query --file and --stdin take one. Nodes first, then manual edges.

write_graphml

Write a single GraphML file describing nodes and edges.

write_jsonl

Write JSONL files to dest: nodes.jsonl, edges.jsonl, rules.jsonl.

write_jsonl_single

Write one file, <dest>/graph.jsonl: every node, then every edge, then every rule, each line an object whose "type" is node, edge or rule.

write_parquet

Write parquet files to dest: nodes.parquet, edges.parquet, rules.parquet.